The goal of this project is to evaluate statistical genetic methods for detecting, characterizing, and mapping the genes that influence complex diseases and their precursors and risk factors. The investigators will pursue this goal by continuing the organization of the Genetic Analysis Workshops (GAWs). The Genetic Analysis Workshops are a collaborative effort among genetic epidemiologists to evaluate and compare statistical genetic methods. For each GAW, topics are chosen for their relevance to current analytical issues in genetic epidemiology, and sets of computer-simulated or real data are distributed to investigators world-wide. Participants submit the results of their analyses, which are discussed and compared at a 2.5 day meeting. The GAW submissions invariably contain new ideas for methods to handle complex phenotypes. GAW11, held in September 1998, was devoted to problems in genetic analysis of data from the Collaborative Study on the Genetics of Alcoholism and analysis of multiple replicates of simulated data for a multilocus disorder with varying severity and with heterogeneity between populations. GAW11 had 210 participants from the United States, Canada, France, Germany, England, Switzerland, Australia, and Argentina. GAW12 will be held in 2000, and GAW13 in 2002. All planning and data distribution for GAW14 will be essentially complete by the end of the requested period of support in 2004.